Fig. 1, A and B. 



Fig 1. A. Intertidal zone. Bowlder, gravel and sand facies with rich 

 molluscan fauna and sea-weed flora, Digby, N. S. 



B. Intertidal zone. Shingle and small bowlder facies with a rich gas- 

 teropod fauna, Pictou Co., N. S. Photo by H. I. Smith. 



